1. Field of the Invention
The present invention relates to door control mechanisms of the type used for securing and maintaining pivoted doors in closed, locked positions, particularly pivoted or swingable doors of truck bodies, trailers or large cargo containers, and the like.
2. Prior Art
Load carrying compartments of truck and trailer bodies and transport cargo containers typically provide pivoted double doors on the rear thereof for loading and unloading the compartments. In addition, truck and trailer bodies often include one or more single pivoted doors on the sides thereof to facilitate loading and unloading. Because the rear door opening is essentially coextensive with the rear of the load compartment, cross-bracing is lacking and the doors are readily distortable due to the application of skewed loads. Door control mechanisms are used with such doors to retain the doors in a closed position and to reduce or eliminate "racking" of the door panels. Door control mechanisms employed in this capacity typically include elongate shafts extending substantially the full height of their associated doors and having latch members at their ends engagable with keeper members affixed to the door frames or compartment bodies.
Conventional door control mechanisms of this type are limited in their use to doors having a predetermined height inasmuch as their shafts are of predetermined, nonadjustable, length, and have latch members and handle attachments welded thereto. Consequently, a manufacturer of trailers employing doors of different heights must order and maintain a stock of door control mechanisms of various lengths commensurate with the heights of doors employed in the trailers being manufactured. Maintaining a large inventory of different length door control mechanisms is costly and requires a substantial amount of storage space.
Since truck bodies, trailer bodies and cargo containers are subjected to corrosive environments, it is customary to protectively finish their hardware as by plating. Often times a plated finish is overcoated with a layer of thermosetting polymer to enhance corrosion resistance. Once this hardware has been protectively finished, it cannot be subjected to welding operations or the finish will be destroyed. Accordingly, it is customary for all fabrication steps which would disturb a protective finish on container hardware, such as welding, to be effected at the factory prior to the application of a protective finish. Approaches which conflict with this practice are not found to be readily accepted in the industry, particularly where the resulting product has an appearance different than that of previously accepted products.